


Falling Through the Cracks

by nutmeag83



Category: Neverwhere - Neil Gaiman, Sherlock (TV)
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Fantasy, London Below, M/M, canon divergence - s3
Language: English
Status: Completed
Published: 2016-08-22
Updated: 2016-08-22
Packaged: 2018-08-10 10:56:15
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 6,830
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7842130
Author URL: https://archiveofourown.org/users/nutmeag83/pseuds/nutmeag83
Summary: <blockquote class="userstuff">
              <p>A crossover of sorts with Neil Gaiman's <em>Neverwhere</em>. </p><p>Sherlock's apparent suicide puts John in a bad place, causing him to fall into London Below. When Sherlock appears almost two years later, he can't understand why he's the only one who remembers John.</p>
            </blockquote>





	1. John

**Author's Note:**

> I wrote this in the middle of the night when I couldn't sleep. I read it through a few times for obvious errors, but I'm sure I missed some. Un-betaed and un-Brit-picked.
> 
> The Teen rating is only because I drop the f-bomb a few times. No smutty bits to be found round these here parts. ;-)
> 
> If you haven't read Gaiman's excellent novel _Neverwhere_ , this probably won't make a ton of sense to you, seeing as I didn't go into long explanations for Gaiman's world. Also, shame on you. You should go read it right now. It's amazing. However, if you decide to read this anyway, below is a bit of background. If you have read _Neverwhere_ , good for you. You're awesome. You can skip this part.
> 
> London Below is peopled with those who fall between the cracks of reality. Those with no purpose or home or someone to love them. Anyone from London Above who has extensive interaction with London Below also become part of that world. When they fall, they are completely forgotten by anyone from Above who had any interactions with them previously. If they manage to speak with anyone, the conversation is forgotten by the other soon after. These people live in places in London that have also fallen through the cracks--old tube stations, forgotten buildings, land from long time past. Magic is heavily present in London Below. Rats are regarded highly and can speak to humans. The House of Arch is a family with the power to open anything (locked doors, walls, people's chests). Links exist between London Above and Below, allowing people to move between them with ease. It's a dangerous, dark place that is nevertheless filled with beauty and magic. I personally would pick to live in Night Vale over London Below, but some people love it. ;-)

**Summary for the Chapter:**

> John has a hard time without Sherlock. This causes him to disappear from the world he knew.

Sherlock’s funeral was only four months gone when John Watson fell through the cracks. He had tried, after the events at Bart’s, to put a life together, but he no longer knew how to function without Sherlock or excitement. Sherlock had talked often enough of his danger addiction, and John tried to feed it, first by getting at job at A&E, then, when that failed to stave off the depression, by going out into the streets at night. His first thought was just to get in as many fights as possible, but once, after fighting some thugs off of a young couple, he decided to help people, as he was made to do.

So he rescued the poor souls on the streets, those who needed his help. It provided some comfort, but the depression never really went away. Maybe, if Sherlock had still been around (but unable, for whatever reason, to provide that element of danger John needed), he would have gotten better. But on one of his bad nights, when there had been no one to rescue or fight with, he’d had the thought that he didn’t matter anymore. And, after that, he didn’t. He stopped being seen by almost everyone. And those that could be bothered to see him (Mrs. Hudson, Lestrade, Harry), forgot about him moments after their conversation ended.

It had bothered him a bit, of course. But the intrigue of no longer being seen by anyone, of being forgotten by friends and family (whom he had avoided since the funeral anyway), snapped him out of the bout of depression. By then, though, it was too late. He had slipped well and truly. He was now a full-fledged member of London Below, though he didn’t know that quite yet.

John Watson was resourceful, despite Sherlock’s many words to the contrary. He managed to pack up a few essentials before his landlord got a hold on his things, then walked around London. He realized fairly quickly that people’s eyes passed over him like they passed over the homeless. This led him to two thoughts. First, if Sherlock had still been alive, would he have been able to see John? He saw so much more than the average (or even above average) person, and he also utilized the homeless network in ways no one else had thought to. Swiftly following that thought was that, even if Sherlock would not have been able to see him, maybe the homeless themselves would be able to.

So he’d searched. He didn’t know their locations like Sherlock did (had), but he remembered a few times Sherlock had dragged him along to pass off information, so he scouted out those spots first. They turned up empty, but as the night got cold, he happened upon a small group attempting to keep warm around some sort of battery-operated heater.

He was seen and recognized by two of them, who introduced him to London Below. It was a dark and dangerous place, but it was also magical and amazing, and John lost count of the number of times he wished his best friend could have seen it.

But Sherlock was gone, and John learned to live without him. Didn’t have a choice, really, if he wanted to stay alive. Luckily, his skills as a upworld doctor were sorely needed, and he was afforded a bit more safety than most people garnered. It helped that he was kind and willing to treat anyone, no matter who they were. But he was also shrewd. Just because he’d treat anyone didn’t mean he trusted them. And so he got along, often muttering the words Sherlock had hurt him with so long before: _Alone protects me_.

And for over a year, alone did protect him. He worked with others when he had to, made temporary truces with the less savory and acquaintances with those who could almost be trusted. But he vowed never to make another friend, to never fall in love again, because doing that was what had landed him there, in the world of shadows and magic.

\----------------

John was making a hospital run when his life changed yet again. Even after a year of living in London Below, he felt a bit of remorse at “borrowing” medical supplies from London’s hospitals. But he was a modern doctor living in a mostly feudal society that didn’t even bath properly, let alone sterilize surgical implements or manufacture penicillin.

Often he traded with someone else to lift the supplies for him, but when he needed particular medicines, he went himself, not trusting his “colleagues” to be able to read. He’d gone to Bart’s, feeling at least a little less guilty stealing from there, seeing as the institution had taken years of his life back during med school. Plus, the quickest bridge to his area of London Below wasn’t far from the hospital, which was always a plus when carrying heavy supplies.

He’d just left the building, flicking a sarcastic salute at the security guard who never noticed him, when someone called his name. The voice was one he could never, ever, in a million years forget, but the tone was foreign. It was filled with disbelief, relief, and quite possibly longing.

John would have dropped the sack cradled in one arm, but there were glass bottles that needed to be kept in one piece, preferably with their contents still inside them, so he managed to keep a tight grip before it fell.

He was also trying to keep a tight grip on his sanity, but it was a closer thing. No one said his name like Sherlock had (did?), and hearing it again made his eyes drift close in relief and happiness and love. Somehow, the impossible was happening to him for a third time (the first being Sherlock’s death, the second his own fall into London Below). John opened his eyes after a moment, then slowly turned, afraid he’d imagined Sherlock’s voice calling his name.

But no, standing directly behind him, arm outstretched as if to touch him, was his best friend, the man he loved more than life itself. Sherlock looked stunned, afraid, and as if his greatest dream had just come true.

Sherlock lowered his arm. “You’re real. _Please_ , John, _tell_ me you’re real.” And again John heard Sherlock’s voice in a tone foreign to his ears. Sherlock sounded broken. He forgot, in his shock, to be surprised that Sherlock could even see him (but of course he could, Sherlock saw everything).

John tilted his head, studying his friend. Sherlock looked to have aged ten years. His face was haggard, and he looked like he hadn’t slept properly in months. John had seen Sherlock tired, worn down by a case, faint with hunger when he forgot to eat, but he’d never seen Sherlock like this. He tried for a soothing tone. “Of course I exist.”

Sherlock gave a choked laugh, sounding a bit manic. “And you remember me? Our life together?”

“It’s everyone else who forgot, not me.”

“Oh, thank God,” Sherlock choked out. “I mean, not that everyone forgot you—and how did they; how _could_ they—but that you remember me. I thought I was going mad. I came back from cutting down Moriarty’s network, ready to jump back into our old life, only to find that no one remembered you. Not Lestrade or Molly or Mrs. Hudson. Not even Mycroft. He said I had PTSD, that I’d cracked a bit after almost two years of hiding and seeing terrible things. But I knew, I _knew_ you were real. I knew I didn’t make you up just because I was lonely. I found that jumper of yours that I burned a hole in and your RAMC mug in my wardrobe. That helped for a while, but when I showed Mycroft, he said maybe I got them to feed my delusions. I’ve been hiding from him for the last few weeks, trying to find you. I found someone in the homeless network who remembered you, said he saw you sometimes at Bart’s, so I’ve been staking it out. Oh God, we need to hide. Mycroft is sure to spot me soon.”

John was about to push him toward his London Below entrance when his brain finally caught up with him. He was so happy to see Sherlock again. Happy that Sherlock _could_ see him. He wanted nothing more than to wrap the man in the tightest hug ever and never let him go. He wanted to sink into the sound of Sherlock’s voice, revel in his smirks, and burrow into that damned Belstaff he was still wearing. He wanted to punch Sherlock, then snog him senseless, then introduce him to the wonders of London Below. He wanted to ask why Sherlock had lied to him and abandoned him. Why he let John fall through the cracks. But he couldn’t. To do any of those things would be to bring Sherlock into the world of London Below, and to take his consulting detective away from the world he knew and loved and hated would be to cut off an arm or a leg. He would be bereft without The Work.

And so John did the hardest thing he’d ever had to do (worse than anything from the war or London Below). He pulled Sherlock into any alley to get them out of sight, then he stepped away from the only person he ever really, truly cared for in years and said, “You need to go now. You need to forget that you ever saw me. Forget that we ever met.” John sucked in a pained breath. “Delete me.”

Sherlock stared at him in horror, mouth gaping. John couldn’t bear to leave him like that, so he waited. He wouldn’t be able to tell the man much, but he would try to answer a few questions in hopes of persuading his best friend to leave him of his own volition. Sherlock’s brain finally rebooted, apparently, because he closed his mouth with a snap and his face hardened.

“What happened, John? How did you make everyone forget you? _Why_ did you do it? What are you mixed up in? Don’t try to protect me. I’ve been aching to see you for almost two years, you’re not going to fucking tell me to _delete_ you. Not now. Not ever.”

John sighed and rubbed his eyes with his free hand. There was a spot nearby, not part of London Below, but not part of London Above either. It would keep them safe for a while. He nodded and motioned for Sherlock to follow him.

“I can’t tell you much,” John began once they reached the hidey-hole. “Basically, I fell between the cracks of London. You know how people’s eyes just sort of glide over the homeless?” Sherlock nodded. “That happened to me. One day, people stopped seeing me. Forgot they ever even knew me. Even Harry. I can have limited interactions with people I knew well, but they forget they talked to me moments later. Everyone else in London Ab—“ John stopped himself from finishing the word. The less said about actual locations, the better. “…in London, can’t see me at all. Well, not just me, but people like me as well.”

“But I can see you,” Sherlock persisted. “I remember you, everything about you. You’re John Hamish Watson, late of the Royal Army Medical Corps, more recently of 221B Baker Street. You have one sister, Harriet Watson. You do locum work at a surgery, hate the color red, talk in your sleep, and are my best friend.”

John sighed. It felt amazing to be remembered. To be remembered by _Sherlock_. “I think you see and remember me because you see and remember so much more than anyone else. You’ve used the homeless network for years. You’re trained to see what others don’t.”

“But Mycroft—“

“Doesn’t care about the homeless unless it benefits him somehow. He didn’t interact with them, and he wasn’t my best friend. So despite the fact that his skills are on par with your own—“

Sherlock growled, and John couldn’t help but grin for a second.

“…close to but still not above your own skills, he hasn’t trained himself to see what you see.”

Sherlock contemplated John’s words for a moment, then nodded. “So why are you asking me to delete you? If you remember our life, don’t you want to try to get it back? Don’t you—“

And, for once, John knew what Sherlock had almost said. Could read it in the man’s eyes. Sherlock was more vulnerable and open than John had ever seen. He was beautiful and heartbreaking, and John really didn’t want to be doing this. Didn’t want to push his best friend away. Wanted to be able to stop thinking that alone protected him.

“Of _course_ I miss you, Sherlock. Of _course_ I want my old life back. But it’s just not possible. And any long-term interactions you have with me could suck you into the world I live in now. And that can’t happen. You have to stay up here, where you can continue The Work. To solve murders and find missing kids and forget things like the basic facts of the solar system.”

“ _Up_ here?” Sherlock questioned, eyes darting around as they did when he was deducing. “So you’re down somewhere? Underground? Earlier you stopped yourself from saying London Above. Is that literal or figurative?”

John cursed. Of course Sherlock would catch John’s slip of tongue.

“You can’t know these things, Sherlock. You have to go home. Delete me. Get on with your life.”

John began walking out of the alley. He thought Sherlock might follow, despite John’s stay-away attitude, but he didn’t hear his friend’s footsteps. After a moment, though, Sherlock’s voice followed him down the alley.

“If I delete you, I might as well have died for real two years ago. Because the only thing that kept me going while I was away was the thought that I’d get to come home to you again someday. Without you, I might as well be dead.”

John stopped in his tracks halfway through Sherlock’s speech. Could Sherlock possibly feel the same for John as John did for him? Well no, not quite. Sherlock didn’t have emotions the way normal people did. Didn’t have the same physical cravings as most people did. But the words he just said might as well have been “I love you. I love you. I love you. I love you.”

John breathed deep and turned around, trying not to hope. “Are you _certain_ you’re ready to give up your life as you know it? To never see Mrs. Hudson or Lestrade or Molly or even Mycroft ever again? To have everyone else look through you as if you’re not even there? To never solve another crime with Scotland Yard? For people to just shrug at your brilliance as if it’s an everyday occurrence?”

Sherlock laughed. “I will get to see you, and you will see me. I can solve crimes just fine without the Met. And _you_ will never shrug at my brilliance.”

John’s chest tightened. Sherlock needed him above anything else. The thought gave him the courage to hold out his hand and make an offer. “Then I’ve got something to show you that will leave you intrigued for years to come.”

Sherlock took John’s hand. “I’ve already seen the intriguing. His name is John Hamish Watson.”

One day, John would ask why Sherlock left him behind. It had been a mistake. It had led him to the life he lived now. But with Sherlock’s hand in his, ready for whatever adventure John had in store for him, John had a hard time begrudging the error.


	2. Sherlock

**Summary for the Chapter:**

> Why is Sherlock the only person who remembers John?

Sherlock Holmes returned to London beaten, exhausted, and nearly broken. His almost two years away had lacked the thrill he had come to expect from solving problems. It wasn’t just that he was working on the same problem for the entirety of his time away (though that played heavily into the equation), but more that John Watson wasn’t by his side to help him and keep him from going to too dark a place.

Sherlock had lived under the radar, unable to show off his prowess (except to Mycroft, who didn’t count and who was no longer a face, but just a series of coded messages); he had no one to ask him questions or laugh with him or watch crap films with. He couldn’t count the number of times his hand had reached for his phone, wanting to ring John up and tell him how horrible this mission was and to demand that John find him a new case. Only a few months in had him realizing that the phrase “alone protects me” was completely wrong. No, his blogger—his best friend—protected him. If John had been with him (like he’d wanted, stupid Mycroft), they would have brought down Moriarty’s network in half the time.

But he was home now. He and John would be a team again, would go on cases and laugh at crime scenes and complain about how boring and plebeian everyone else was. Sherlock would be able to look up from his laptop and see the man who meant everything to him sitting in the chair opposite, a smile on his face as he looked up from his own computer or a book. Sherlock even couldn’t wait to hear John be boring and complain about the kitchen being a mess, because it would mean John was alive (the whole reason for this bloody ruse) and with Sherlock again.

John had kept Sherlock sane during their time apart. Sherlock would talk to an imaginary John, explain what he was doing, sometimes even argue with him, just to pretend for a few moments that things weren’t absolute shit. It was easiest to do when he was coming out of his mind palace. Back at 221B, during those first few moments after surfacing, more often than not John wouldn’t be there anyway, so it was easy to pretend he’d just gone to the shops or the bookstore or to have lunch with Mike or Lestrade.

There was no need to pretend anymore, though. 221 Baker Street would have all of its rightful residents back under its roof by the day’s end. Had John stayed there after Sherlock left? Sherlock couldn’t imagine his friend being anywhere else, but sentiment did funny things to people (Sherlock included, though he was still loathe to admit it).

Before he could go home, though, he had a debriefing with Mycroft to attend. Bloody Mycroft. Sherlock had gone over everything with his brother in Serbia, what was there left to say? At least he could have Mycroft tell him where John was, rather than go looking for the man himself. He was tired and not up for traipsing around the city.

Paperwork complete, Sherlock slouched in the chair in front of Mycroft’s desk. “Where’s John?”

His brother’s face was pleasantly (Mycroft thought at least) blank. “Who?”

Sherlock rolled his eyes. “Not now, Mycroft. I just got back. All I want to do is talk to my best friend and sleep for a week.”

Mycroft lifted his eyebrows, but otherwise kept his face impassive. “Sentiment is a weakness found on the losing side, brother mine. Why on earth would you have a friend, let alone one you could call best?”

“That may be true, but even a high functioning sociopath finds the need for a helpmate from time to time,” Sherlock spat back. “So quit pointing out my weaknesses and tell me where John is.”

Mycroft only stared at Sherlock.

Sherlock straightened. Something wasn’t right. “Dr. John Hamish Watson, formerly of the Royal Army Medical Corps. The man who followed me on cases for the two years preceding my timely ‘death.’ Short. Blond. Cares too much.”

Sherlock knew the look on Mycroft’s face. It was the oh-dear-god-my-brother’s-gone-off-the-deep-end-again look.

Sherlock stood abruptly, unnerved. “Never mind. He’s no one. I’ll be going now. Must see Mrs. Hudson and get settled back in at 221B. Lack of sleep. I’m not feeling well. Goodbye, brother.”

\----------------

No one knew who John was. Mrs. Hudson asked if John was someone Sherlock had found to flatshare with (after beating him about the shoulders for tricking her for two years). Lestrade looked at Sherlock as if he was barmy (or high). Molly had just shrugged and giggled nervously. Mike had said “You know, I think I went to school with a John Watson… but it’s a horribly common name, so who knows,” and had just grinned at Sherlock as he was want to do.

Sherlock spent the next few weeks researching, looking up every John Watson in the whole of the UK, but there was no sign to be found of _his_ John. He wasn’t listed in the RAMC files, nor in the birth records for his home town. He even called Harry, who told him she was an only child, thank you very much for bringing that up, you bloody idiot.

Finally, he checked all the clinics and hospitals. No Dr. John Watson of the appropriate age to be found. No John Does with lost memories that fit John’s description. Nothing. John was just gone. Vanished. It was as if he had never existed.

But he _did_ exist. Sherlock had two years of memories and another two years of longing to prove it. But what if John was all in his head? He had spent two years talking to an imaginary John. What’s to say the two years previous hadn’t also been in his head? But no. John had saved him during their first case. Hadn’t he?

Sherlock questioned his sanity until he found John’s jumper that he’d accidentally lit on fire during a particularly fascinating experiment. The next day, he found John’s RAMC mug buried at the bottom of his wardrobe. Proof! John did exist. The jumper even smelled very faintly of John’s aftershave (and burned wool…).

Had John hidden them for Sherlock to find? A sign that he had gone away but did truly exist? Was he in trouble? Did he need Sherlock to find him? Bring him back?

Sherlock stormed into Mycroft’s office the same night he found the mug, carrying his bundle of proof.

“See? John does exist. These are his things.”

“Hello, brother mine. So glad you could drop in. I do so love our bonding time.”

Why did Mycroft insist on being so bloody difficult? Sherlock dropped the cardigan and cup on his brother’s desk. “Shut up, Mycroft. Look! John’s jumper that had an unfortunate accident with a Bunsen burner. The RAMC cup he drank out of every day. These are John’s things. He does exist. I just have to find him. Did you make him disappear? What did he do? Uncover some government plot? Is there some sort of experiment going on that erases people from existence? I demand to know what happened to John!”

He really shouldn’t have even come here at all. He knew, deep down, that Mycroft really didn’t remember Sherlock’s best friend. Which meant that either Mycroft’s memory was erased or…John really didn’t exist. In either case, Sherlock insisting John was real was only going to get him put in a mental hospital. But he couldn’t stop talking. He hadn’t slept in a week, had consumed more coffee and nicotine than was remotely healthy (John would yell at him so much; and Sherlock would dearly love to hear that rant right about then), and he really needed to know what had happened to his best friend.

“You have to help me find him, Mycroft,” Sherlock continued, desperate. “Dr. John Hamish Watson. Army captain. Fifth Northumberland Fusiliers. Wounded in Afghanistan. Discharged in 2009. We met in January 2010, during the Study In—“ damn, no one would know that title, if they didn’t remember John. “…the suicide-murder cases. Wait, how did I survive if John wasn’t there to shoot Hope for me?”

“Ah, you mean the Jeffrey Hope case? Someone did shoot and kill him, yes. We never found out who it was. Annoyed me for a whole week…” Sherlock knew Mycroft was barely paying attention to what he was saying. He was focused on trying to figure Sherlock out, deciding whether his brother really did need to be locked away for his own safety.

“I know the past two years have not been easy on you. Being away from the job and city you enjoy. It was lonely, I’m sure. You’re used to your landlady and that DI being around to be impressed by your deductions. It’s possible you created an…imaginary person to talk things through. Expected, really. You do work best when you have someone to bounce ideas off of. But you’re home now, Sherlock. There’s no need to acquire items to feed your delusions. We have people you can talk to. People who work specifically with PTSD sufferers. You can go back to working with the idiots at the Yard and having your landlady bring you tea and biscuits. It’s time for you to go back to your old life.”

That’s exactly what he wanted back, his old life. It was no use. Mycroft couldn’t help him. Sherlock was on his own. He _would_ find John. He _had_ to. If John no longer existed (or never had), then there was no reason for Sherlock to live. Who was he without his blogger-doctor, without someone to tell him he was brilliant and help Sherlock see more clearly than he could alone? Sherlock couldn’t even imagine such a life anymore. Yes, he would find John. He would exhaust every avenue. He would die trying.

\----------------

Mycroft’s men came for Sherlock two days later. He was able to give them the slip and go into hiding. He had been with the homeless network for an entire day before he thought to ask if they knew where John was. Or if they remembered him at all. Most gave him the same confused looks everyone else had, but one finally looked away shiftily when Sherlock asked, and he refused to leave the boy alone until he told him what he knew.

“Look, just forget that bloke, mate. It’s no use. He’s gone.”

Sherlock slammed the boy against the wall, not caring that John would have yelled at him for it. “Tell me what you know. Now.”

The boy sighed, but looked resigned. “I’ve seen him around a few of the hospitals. Bart’s mostly. University College a few times. But really, you should just forget about him. It’ll only get you in trouble.”

“Why?” Sherlock pushed his forearm harder into the boy’s chest. As if he’d quit just as he was finally getting somewhere with this blasted fiasco.

“Because things exist that don’t follow the rules you’ve always believed in. Dark, dangerous things. And investigating them will only have you falling into them, too. And you’ll never get out. So go back to solving crimes, alright?”

The boy caught Sherlock unawares with a kick to his shin and an elbow to his stomach, then took off running.

Sherlock knew there was no use in giving chase. He had all of the information he was likely to get from the boy anyway. So he staked out Bart’s (didn’t bother with University College, given that John frequented it less than Bart’s), hoping to catch a glimpse of his friend.

It was another two weeks before he spotted John walking through the front doors of Bart’s. Yes! It was really him. His best friend was alive and well, if looking much more hardened than Sherlock was used to. He didn’t even try to be sneaky. He waltzed into the hospital as if he belonged there (or as if no one could see him, which almost seemed to be the case…). Sherlock stopped himself from running after him. John had an empty knapsack on his back, which meant he was planning to leave with it more weighed down than when he went in, which in turn meant he’d be easier to catch if he decided to run.

Almost an hour later, John exited the building, and yes, his pack was full and he carried another sack in the crook of his right arm. Sherlock couldn’t stop the “John!” that came to his lips, and he tore after the man, following him down the sidewalk. God, it was really him. He existed. Sherlock wasn’t cracked or suffering from PTSD. His friend was right in front of him.

John froze in his tracks. Sherlock reached out a hand to get him to turn around. He _needed_ John to turn around, needed to see the man’s face. He _needed_ to touch him. But before his hand reached John’s shoulder, John slowly pivoted on one foot.

His eyes were wide with disbelief, his face frozen in shock. But the look in his eyes. Recognition. Relief. But otherwise, his face showed no emotion. He stood as ramrod straight as he had the day he and Sherlock had first met, as he did anytime he was threatened or questioned. Was he afraid of Sherlock? Why? Did he think he was seeing a ghost? John had been led to believe Sherlock was dead, after all.

“You’re real,” Sherlock said, lowering his arm. “ _Please_ , John, _tell_ me you’re real.” Was that his voice? He sounded so…broken, pleading. It must be the lack of sleep. He wasn’t thinking straight, was more prone to flights of sentiment. But he’d found John, so things would be put to rights. They would find a way to make everyone remember John, to go back to their old life.

John tilted his head, studying his friend. Up close, Sherlock could see how John had aged. Life had not been easy for him the past few years. His tone, when he spoke, was soothing. “Of course I exist.”

Sherlock gave a choked laugh. He knew he sounded a bit manic, but didn’t care. John was real! “And you remember me? Our life together?” He held his breath. What if John didn’t remember Sherlock? Didn’t remember their life together? Sherlock didn’t think he would make it if John, the one person who had ever really cared about him as an adult, didn’t remember him.

“It’s everyone else who forgot, not me,” John replied softly.

“Oh, thank God,” Sherlock choked out. He babbled, unable to make his mind work properly. “I mean, not that everyone forgot you—and how did they; how could they—but that you remember me. I thought I was going mad. I came back from cutting down Moriarty’s network, ready to jump back into our old life, only to find that no one remembered you. Not Lestrade or Molly or Mrs. Hudson. Not even Mycroft. He said I had PTSD, that I’d cracked a bit after almost two years of hiding and seeing terrible things. But I knew, I _knew_ you were real. I knew I didn’t make you up just because I was lonely. I found that jumper of yours that I burned a hole in and your RAMC mug in my wardrobe. That helped for a while, but when I showed Mycroft, he said maybe I got them to feed my delusions. I’ve been hiding from him for the last few weeks, trying to find you. I found someone in the homeless network who remembered you, said he saw you sometimes at Bart’s, so I’ve been staking it out.” And damn it, he’d been in one spot for too long. They needed cover _now_. “Oh God, we need to hide. Mycroft is sure to spot me soon.”

John looked around, then pulled Sherlock into a nearby alley. They needed to move further, but Sherlock thought this would do for a short time. John stood tantalizingly close for a few seconds before backing up. “You need to go now. You need to forget that you ever saw me. Forget that we ever met.” John sucked in a breath. “Delete me.”

No. This wasn’t right. John was supposed to be happy that Sherlock had found him, should be jumping for joy at being remembered. What the hell had happened to him? Whatever it was, they would figure this out.

“What happened, John? How did you make everyone forget you? _Why_ did you do it? What are you mixed up in? Don’t try to protect me. I’ve been aching to see you for almost two years, you’re not going to fucking tell me to _delete_ you. Not now. Not ever.” God damned sentiment. He rarely cursed. His mind could come up with much more descriptive language than that. And why had he used the word aching? He had missed John fiercely, yes, but that didn’t mean he needed to spout ridiculous tripe at the man.

John sighed and rubbed his eyes with his free hand, as he did when he was thinking or upset. Then he nodded and motioned for Sherlock to follow him.

“I can’t tell you much,” John began once they reached the hidey-hole John had led them to. Much more effective than the alley, Sherlock noted. “Basically, I fell between the cracks of London. You know how people’s eyes just sort of glide over the homeless?” Sherlock nodded. “That happened to me. One day, people just stopped seeing me. Forgot they ever even knew me. Even Harry. I can have limited interactions with people I knew well, but they forget they talked to me moments later. Everyone else in London Ab—“ John stopped himself from finishing the word, but Sherlock knew what he’d almost said. What was London Above? That had to mean there was a London Below, yes? Was John living in the sewers? But no, it had to be more than that. John moving to the sewers wouldn’t have erased him from all memory and written records.

John continued, correcting himself. “…in London, can’t see me at all. Well, not just me, but people like me as well.”

“But I can see you,” Sherlock persisted. “I remember you, everything about you. You’re John Hamish Watson, late of the Royal Army Medical Corps, more recently of 221B Baker Street. You have one sister, Harriet Watson. You do locum work at a surgery, hate the color red, talk in your sleep, and are my best friend.”

John sighed. “I think you see and remember me because you see and remember so much more than anyone else. You’ve used the homeless network for years. You’re trained to see what others don’t.”

But Sherlock wasn’t the only one who saw more than most people, pained though he was to admit it. “But Mycroft—“

“Doesn’t care about the homeless unless it benefits him somehow. He didn’t interact with them, and he wasn’t my best friend. So despite the fact that his skills are on par with your own—“

Sherlock growled, and John let loose a moment’s grin, which had Sherlock almost melting in relief and happiness at seeing it again. This was _his_ John alright.

“…close to but still not above your own skills, he hasn’t trained himself to see what you see.”

Sherlock contemplated John’s words for a moment, then nodded. “So why are you asking me to delete you? If you remember our life, don’t you want to try to get it back? Don’t you—“ Sherlock cut himself off. He really needed to sleep. If he finished that sentence, if he let his weakness show….

But John knew him too well. He smiled at him sadly. “Of _course_ I miss you, Sherlock. Of _course_ I want my old life back. But it’s just not possible. And any long-term interactions you have with me could suck you into the world I live in now. And that can’t happen. You have to stay up here, where you can continue The Work. To solve murders and find missing kids and forget things like the basic facts of the solar system.”

Why was John so selfless? Why couldn’t he be selfish just for once?

Sherlock asked the question that had been niggling at his brain. “ _Up_ here. So you’re down somewhere? Underground? Earlier you stopped yourself from saying London Above. Is that literal or figurative?”

“Fuck,” John mumbled. “You can’t know these things, Sherlock. You have to go home. Delete me. Get on with your life.”

John began walking out of the alley. No! John couldn’t leave. They had a discussion to finish. He couldn’t let John walk away without knowing…

“If I delete you,” he called to his friend’s retreating back, “I might as well have died for real two years ago. Because the only thing that kept me going while I was away was the thought that I’d get to come home to you again someday. Without you, I might as well be dead.”

God, why did he say that? He was overwhelmed, he was exhausted, he was watching the retreating back of the friend he’d thought had been completely erased from the world. He shouldn’t be speaking at all.

After a moment’s pause, John turned around. He looked worried and scared and so damned hopeful that Sherlock almost reached out to pull him close. To shake him and say, _Don’t you understand? I can’t live without you! I_ need _you. Take me with you!_ But he kept his mouth shut.

“Are you _certain_ you’re ready to give up your life as you know it? To never see Mrs. Hudson or Lestrade or Molly or even Mycroft ever again? To have everyone else look through you as if you’re not even there? To never solve another crime with Scotland Yard? For people to just shrug at your brilliance as if it’s an everyday occurrence?”

Sherlock’s laugh was one of relief and fondness. John was such an idiot. “I will get to see you, and you will see me. I can solve crimes just fine without the Met. And _you_ will never shrug at my brilliance.”

John held out his hand. “Then I’ve got something to show you that will leave you intrigued for years to come.”

Sherlock took John’s hand without a thought. It felt natural. Right. “I’ve already seen the intriguing. His name is John Hamish Watson.”

John grinned. “Okay, then. A close second.”


	3. Epilogue

**Summary for the Chapter:**

> Let's wrap this up, folks.

And so John showed Sherlock a world he never could have imagined existing (okay, maybe he could have imagined it when he was seven years old). It was dark, it was dangerous (but they thrived on danger, so that was okay), and it was just as intriguing as John promised. Sherlock loved it almost instantly, well, once he got over being annoyed that it often broke the laws of physics and logic. He had a new playground to play in, and his best friend was at his side.

Were they more than friends now? It was different between them than it was before, and not just because they lived in London Below. John still followed him around, helping Sherlock solve cases and riddles and making sure the innocent were safe and free, but instead of retreating to separate places when they settled down for the evening (John had procured a nice, quiet set of rooms after saving the life of one of the members of the House of Arch), they stayed near each other, as if they each were afraid the other would disappear if they were too far apart.

When Sherlock laid down to read one evening, he put his head in John’s lap, and John began carding his hand through Sherlock’s curls as if they did that every day. And after that, they did. When John nagged Sherlock to get some sleep a few weeks later, he pushed Sherlock toward his own room (Sherlock had been kipping on the couch) and joined him there soon after.

They came to be known throughout London Below as the Healer and his Detective, and Sherlock did not mind the use of the possessive in the least. Because John had done just fine without Sherlock during his first years alone, but Sherlock knew he would not be have been fine without John by his side.

And they were never apart for long again. Bad things happened to them, just as they had in London Above, but each worked hard to get the other back when necessary.

Sherlock learned the tunnels of Below just as he already knew the rooftops Above. He knew where every bridge that connected the two cities was located. John was the best healer in the land, and garnered more favors than even Sherlock did, which allowed them to live in relative comfort, even if the occasional kidnapping still happened.

And if John held Sherlock closer than usual after their brushes with death, well, Sherlock rather liked it. He was with his best friend doing what he loved; that was all that mattered.


End file.
